AA Flashlights - "Cockroach" / "Vampire" / "Drain-me-till-I'm-empty"

Typically what we call sensor resistors are low-Ohm, high-wattage buggers that are expensive and less common. In this driver, though, a run-of-the-mill 0805 1/8 or 1/16 watt resistor like you can get in bulk kits from places like Banggood, AliExpress, eBay, or any electronics supplier for like $0.01 each will work just fine.

I can definitely build them and send them your way. But if you can locate the parts locally, it’ll probably be considerably cheaper to do so.

Nope, this was designed to be extremely simple with no modes… just extended runtime. Running an MCU would require extra power and would decrease runtime. Lit tailcaps are also a no-go (unless perhaps my “booster tails”) as they would still be seeing the ~1.2 volts of the battery, no enough to run a typical tailcap.

Lower voltage shouldn’t be a problem. It should operate LEDs with a vF anywhere between 1.3 and 5.0 V.

I think so. I can play with the layout and see if 10mm will fit. Some AAA drivers have lobes on them. Are you thinking completely circular, or odd-shaped like that of the Astrolux A01 or Lumintop Worm or Tool AAA? Do you have a specific host in mind?

Ah ok thanks, let me look into the resistors again.

For the capacitors I found 6.3V and 10V, does it matter which one or will both work?

Either is fine.

I’d probably go with 2 0.5-1 lumen and 2 in the 3-5 lumen range. Let me know when you are ready!

Ok. Diameters?

Do you have an Oshpark link and BOM for the ZXLD381 version as well?

Yup, here ya go

https://oshpark.com/shared_projects/eRMnLVjU

BTW, I found some 381’s on AE. Granted, it’s for 30 pieces. So yeah… I’ve got 30 of these sitting around unused. :frowning:

My SpiderFire C-013 used to work down to 0.7 Volts. However, it needed something like 0.9 Volts to turn on first. I actually fed it weak AA batteries. IIRC, the one I had was advertised as a 3-mode but ended up being a 5-mode.

@ gchart

In case you need payment in advance to get materials for the drivers or something related, please let me/us know!

And thanks in advance for your work :+1:

Hey buck91, were you wanting all 4 in 17mm?

Shouldn’t need payment up front, but I’ll let you guys know via PM before I ship them out to arrange payment.

Have you been able to locate what you need? Or do you think you might have me build them?



@All: It’s been ~5 days… Do I call it at this point and order the parts? Any more interest out there?

I’d go with 17mm for the T2 host.

Struggling to find CDRH5D28 inductor locally atm. Looks like a specific brand/type of inductor? Can it be substituted with a standard case/package? Ideally I’d like to buy from RS .

I think I can find all the other parts so this will be a nice little project.

Will you be uploading the 15mm versions in the future? Do you know the safest size it could be shaved down to?

The CDRH5D28 is just a somewhat common (especially on AliExpress) inductor by Sumida. It’s footprint is 5.7 x 5.7 mm.

Anything in that size ballpark (say 5x5 to 6x6) should work fine. Something like the Bourns SRN5040 or RS Pro 53 or 54. Just pick your inductance according to the ZXLD381’s datasheet (47uH = 6.5mA, 22uH = 15mA, 10uH = 30mA, etc). Heck that RS Pro 53 looks suspiciously familiar… like a store-labelled Sumida.

I’ll upload the other footprints (like 15mm diameter) soon. I wanted to make sure there was interest before spending the time to create them.

Awesome, you’re the best!

One more question :blush: For the TLV61220 version, is a 1206 inductor ok in place of 1210? I could only find inductors with low DC resistance in 1206 footprint.

Yup, 1206 isn’t a problem at all.

I don’t really have a host in mind, but 1xAAA (with a tail clicky) is my favourite format for EDC and my most carried lights are SF-348s which are single mode anyway. I was basically just thinking out loud. I’m not really sure whether 20mA would be bright enough for a general-purpose EDC light.

The Astrolux A01 might be a good choice of host since it’s cheap, readily available, and has a horrible stock driver.

I’m planning to pair the 15mm version of your driver with a red XP-E in a TG06S host to make an astronomy light for my father.

Update: 15mm designs have finally been done and uploaded to Oshpark

ZXLD381 15mm: OSH Park ~
TLV61220 15mm: OSH Park ~

Will be ordering the boards soon.

Awesome! Guess I better figure out what LED I’m using now (thinking a warm or maybe neutral sst-20).

Thanks for the update :wink:
Will be looking for them :+1:

Got my “joule thief” drivers from gchart today :wink:
Seem’s like I’ll have some mods to do :partying_face:

Thanks for your work gchart :wink: